US Patent 7270094 Control apparatus for electric variable valve actuation mechanism

An electric variable valve timing mechanism and a starter are actuated by electricity supplied from a common battery. During an engine starting process, the starter is actuated, and an electronic control unit controls the electric variable valve timing mechanism. The electronic control unit limits the actuation of the electric variable valve timing mechanism on the condition that, during the engine starting process, the voltage value of the battery falls below a predetermined threshold value that degrades the operation of the starter. As a result, the engine is started in a stable manner.